Improvement in sewing-machines



M DI MOGK ING MACHINE;

No. 20,413. Patented June 1, 1858.

. with the catching of the loop.

UNITED STATES PATENT OFFICE.

MARTIAL'DIMOCK. OF MANSFIELD. CONNECTICUT.

IMPROVEMENT IN SEWlNG-MACHtNES.

Specification forming part of Letters Patent No. 20,4l3, dated June 1, 1858.

Too. whom it ma 1 concern.-

Be it known that I, MARTIAL DIMOCK, of

Mansfield, county of Tolland, and State of Connecticut, have invented certain Improvements in Sewing-Machines; and I do hereby declare tainty of action in the single-thread or chainstitch machines, in that part which has to do Itis a wellknewn defect in this class of sewing-machines that the loops frequently fail of being caught upon the looper, and a great variety of devices has been proposed to reinedysaid defeet. This is all the more important, because a stitch dropped in one of these constitutes a serious damage to the seam, consequent upon the easy raveling .of the same. In addition to all this there are other niceties re quired in order to put and keep the said class of machines to work, especially as to the care necessary in the setting of the needles and the exactness of direction of the eye; In my improvement these defects are obviated by means of a device made to act in conjunction with the looper and needle, so as to catch and open the loop by a forcible seizure of the same,

then drawing it out into a'bow, and keeping itso drawn until the looper has entered and caught it up. This result is accomplished irrespective of any particular exactness in the set of the needle, or in the direction of the eye of the needle, provided only that it be at the .right angle, or nearly so, to the direction of the course in which the looper vibrates, and

also in such direction as to cross the path of the needle These grippers are seen at a, and consist of a couple of bows of springsteel, or

hen the same upon it.

other suitable material, of shape seen in Figs. I and II. They are attached to a stock or bar, a, which is so set under the bed of the machine as to receive action, to give the necessary reciproe'ations, by a cam, b, on the main shaft, as shown in Fig. I. Theplacc where the needle comes through the bed is seen at c, and is directly in the way of the grippers was they move back and forth. The points of these would therefore strike the needle. if it were below the table when the gripper-stoek rides up on its cam. The timing of the earn which drives the needle and that which drives the gripper, is so adjusted that at the moment when the end of a rides up on b the needle will be above the table, and consequently out of the way. The-looper is seen at (I, placed upon a l'OCiPlOOttfiilg plate, (1,

driven by a lever connected with the main cam,

as shown. A more particular description is not deemed necessary'hcr'e, as therc'is-a variety of loopers equally applicable. Neither is it necessary to describe the other parts of thennachine, as none are required for this which are not already well known in sewing machines.

The operation is as follows: The needle being threaded and the other wellknown parts' in order for working, the needle standing above the table, the gripper will be at that time in the position shown in Fig. II, so that the bow will inelose the-hole through which the needle descends, and in which position it will remain until the descent of said needle, which will of course pass through or between the grippers. The deepest part of the cam I) now arrives opposite to the end of a, and-the latteris drawn into it by the recoil-spring shown, drawing along the grippers, the ends;

of which grasp the needle as they pass, and are forced open by it in order that it may pass out. In doing this the thread is also gripped; but, being loose at that 'moment, it is carried along with the grippers andinade to how 0 at, as

seen in Figs. I and III, and which position is I thus kept until the looper has entered and ta- The retreating of the needle now draws up the slack of the thread, and the latter is therefore pulled out of the grippers and thus released therefrom. The looper, continuing on, holds the loop-thus taken and spreads it in the path of the'n eedlc,-

ready for that to go through on'its nextstroke,

and as seen in Fig. H, such holding and spreading being, as is well known, ;required' in all kinds ofloopers for chain-stitch inalhe needle now descends, passing th'rolugl'i the loop, when the looper will be withdrawn, as in Fig. I, the grippers then drawing off a loop, as before, and so on suceessively.

v It is obvious that a pair of grippers of this construetion may also be' applied to draw off the I loop'in a shuttle-mnehine for the purpose of insuring the entrance of thepoint of said shut the, there'bein'g spaee'enough between the bed and the upper part of the shuttle for the grip;

pers to move in.

forth herein.

In witness whereof I have vherehiito' sub= scribed my name,

MARTTAL DIMooK:

In presence of- I S. H. MAYNARD, THOMAS Doom.

all 

